Service meter and relay for telecommunication systems



April 18,1944. G.,DEAK|N i I 2,346,910

sEl-RVICE METER AND RELAY FOR TELECOMMUNICATION SYSTEMS Filed Jan. .19. 1942 T0 START T0 START CIRCUIT A TTORNE Y.

Patented Apr. 18, 1944 SERVICE METER AND RELAY FOR TELECOMIVIUNICATION SYSTEMS Gerald Deakin, NewI York, N. Y., assignor to International 'Standard Electric Corporation, New York, N. Y., a. corporation of Delaware Application January 19, 1942, Serial N0. 427,304

l (Cl. 179-8) 9 Claims.

This invention relates to telecommunication systems and apparatus and more particularly to a construction vof combined service meter and relay and to subscribers line circuits incorporating a combined service meter and relay in automatic and semi-automatic telephone and like systems. i

An object of the invention is the provision of a simple and reliable combined service meter and relay. In accordance with a proposed ernbodiment ofthe invention a service meter may, for example, be constructed to respond marginally to two values of operating potential so as to perform the functions ordinarily performed by the cut-olf relay in automatic or semi-automatic telephone systems as well as the normal metering function. Such a unit permits the momentary use of higher than normal potentials for operating'the counting or call meter-v ing mechanism, thus allowing the normal potential to be used for operating the cut-oil springs with ample margin.

A further object of the invention is,therefore, the provision of a subscribers line circuit comprising a service meter provided with contact springs which perform the functions usually performed by the contact springs of the conventional cut-off relay.

The above and other objects and features of my invention will be more fully understood from a reading of the following description taken in conjunction with the attached drawing, in which Fig. 1 is a side elevation partly in section of a structure according to one embodiment of. my invention;

Fig. 2 is an end elevation of the structure shownin Fig. 1 looking from the left;

Fig. 3 is a sectional elevation on the line 3-3 of Fig. 1; and

Figs. 4 and 5 are circuit diagrams showing two examples of subscribers line circuits according -to my invention.

.the spool and armature unit is slid into position,

as will be described subsequently.' 'A'molded spring support`2 is provided for each meter and relay unit, and it is contemplated thatza mounting Apieces 6 by means of a pivot pin l2.

plate l with ten molded supports 2 and spring groups will be assembled as a unit, and the ten magnet structures each comprising a magnet( spool, counting mechanism'and relay armature also constructed and adjusted as a separate unitand then slid into position on the mounting, no wiring or soldering being necessary.

The magnet assembly comprises two side return pole pieces 6, as is customary in standard service meter design, to which are securedl the two spool heads 9'of the magnet spool 8. The spool heads 9 may be secured to the pole pieces 6in any convenient manner not shown in the drawing. At one end of the spool 8 is located an armature l0 which is pivoted to the side pole' A pawl il pivoted at the top'of the armature IE) and ccoperating with a ratchet i6 is adapted to actuate counting mechanism, which may be of' any known and suitable type. A'spring I3 attached to the armature I0 retains the latter inits normal position resting against a pin I4 which is attachedto the side pole pieces 6, as isalso a pin l5 vto which the aforementioned spring i3 is also attached. yA dust-tight cover.A l1 is adapted to slip over the meteringlmechanism and is provided with a window (not shown) through which the number wheels may be read. At the' other end of the magnet assembly a relay armature I8 is mounted on a pivot I9 attached to the side pole pieces G. A roller 2t formed ofinsulating material is mounted on a pivot 2| at the top of the armature Hl. "Norw mally, the armature IB rests against a pin 22 attached. to the side pole pieces 6 and is held in this position by the bent ends 24 of the upper members of the cut-oli spring pairs 3 whichare provided with contacts 3|.

The magnet assembly comprising the magnet spool' 8, armatures l and llil, and the counting mechanism I6, slides into the molded spring support 2 from'the rear. Flanges 23, which are welded or otherwise attached'to the pole pieces 6, engage in slots 24 formed in the molding 2 which, as already stated, is attached to the 4main support I. 'I'he magnet unit is adjusted to operating limits' before being slid into position. The

air gaps 29may -be adjusted by rotation of the octagonal threaded magnet core extensions 25.

These extensions 25 are threaded onto the mag net'core 30, and space in the spool heads' is provided so that they may move backward or or removed without unsoldering or otherwise disconnecting any wires. A cap or-cover 26 -is .slid into position over the left-hand endfofftl'iesstructure after the magnet assembly is in position, and protects the spring contacts and the .relay armature from dust.

As already stated, it is contemplated that the combined units will be mounted ...infstrips Loi ten With a suitable terminal strip for outside .cabling at one end. The space 2 shown enclosed in brokenlines in Fig. l :may conveniently1 accommodate the wiring tothisrccmm'on terminal strip.

The :relay armature sI8 will be v'adjusted :to operate, for example, on '24`4volts lrand `when'attracted will rest against :the Astop fpin .28 provided in the .adjacent core .extension 25. The counting mechanism'armature I0 will befadjust ed to operate on, say 80 yvolts 4when the relay armature I8 .is attracted. It Vwill release `when the -normal potential of y24 volts is restored, thus permitting the combined unit to tbe 'used for multiple .metering lwithout :releasing the relay armature I8. The adjustments Iare lee'cted lby variationof the air-gaps 29 and by the :choice of suitable tensions 'for the spring I3 and :for the contact springs which are 'engaged by the roller 20. I

Fig. 4 shows one Aapplication fof .a combined service meter and ycut-off relay in-a subscriberfs line circuit of thekindprovided withthe'usual line relay LR and forming .part of a .known type of automatic or semi-automatic `telephone system,as disclosed, for example,1in .British Patent No. 141,080, .in which a callinglineisilpicked 1 up by an idle line nder :provided with :four brushes.

When the .subscriber :removes his receiver,`the line relay LR is energized -over thezswitch hook contacts H, the subscribers loop circuit'iandicontacts I and 2 of ,the .combined .service meter and cut-oir relay COM. At --contactsi'l `lin'erelay LR grounds the start A*circuit SSII' and .at :lcontacts 2 connects battery to .the `test .terminals Cfin'the banks of the .line finders. Theqgrounding -of 'the ,start .circuit ST l.causes :an *.idle v.line finder .to hunt for `the calling -Jine :in known manner, and when theacallinglinezisaseizedfbattery is connected to private Wire vterminal P, thereby energizing the `combined :service meter and cut-ofi relay COM to l.such .an extentthat the relay armature opens contacts :.Izandl, but the counting rmechanism is 'not :actuated :The line relayLR is disconnected `from thezsubscribers line. wires land relapses. When `it .is .required .to Imeter the call, metering 'batterypoteritial will be applied to the private wire .terminal P, vior example, from Va link circuit, as disclosed in British Patent `141,080, ,thereby causing .the combined service .meter f' and cut-1oiI relay to operate fully land :actuate the counting mechanism.

Fig. 5 shows how a combinedfser-vice meter and .cut-off .relay v.may be employed in ia `subscribers line circuit :of tlie kind Vdescribed .in

winding and the wiring terminals is automati-` my copending United States application Serial No. 286,220, filed July 24, 1939, in which the usual line relay is omitted, and instead a pair of resistors K and L are normally connected to the a and b wires of the subscribers line circuit. The resistor L is connected to battery and a start circuit continuously tests the free .ends ST .of the `resistors K of .a ,group of subscribers lines, as disclosed'inmy copending application above referred to.

Upon closure of the subscribers loop at switch hookvcontacts H, negative potential is applied to the start circuit over resistor L, contacts I of the combined service meter and cut-01T relay .COMythe `subscribers loop, contacts 2 of COM and .resistor An idle line finder is thereby caused to hunt -for the calling line and when .it arrives .on the terminals A, B, P, C, ground is placed on the terminal C as described in the copending application mentioned above. The line liinder relay designated R in Vthis'copending application, will be .provided ywith additional contacts over Vwhich the normal .exchange battery voltage is -connected to ythe 4private -wire terminal P, thereby causing the relay armature of the combined service meter and cut-oi relay COM to open the contacts I 2, and 3, but the countingmechanism is not actuated. At :contacts I and 2 `the l:resistors K :and L Aare disconnected from the line wires and at contacta@ the lower end of resistor K i'sdisconnected from the test terminal C, .thus holding :the calling line busy.

When a connection has been set up 'to 1a-wanted subscribers line, metering lbattery. 1potenti'a1 will be applied tothe private Wire'terminal 2P, for example, from a link circuit 4or kregister :in any known manner, thereby causing lthe-combined service meter `and cut-'off relay COM zto attract its meter armature .and 'actuate the counting mechanism. Upon removal of .the metering battery, the armature which actuates the counting mechanism will restore, but lthe armature which `opens the contacts I, 2 vand i3 will remain attracted.

Since the resistors K-and L are not connected to vthe line wires :during selection and conversation, they may be reduced .to any convenient value. By using .resistors Tof reduced Lvalue, it is possible to adjust the common start -.circuit so that it will not indicate aline 'as being in a calling condition in lresponse to a :loopfcircuit or leak of a resistance higher than may berhel'd by .the vsupervisory or dialing relays .in theit'alking connection switches or .register circuits. This will reduce the number of false calls. 4Moreover,since the combined service meter and icutoi relay when functioning as a cut-oit relay opens at contacts 3the-.test conductorfextending to test terminal C, ground applied to terminal C by a line nder or connector `:will 'not "affect the start circuit. It is unnecessary, therefore, to insert in the start circuit conductor ST -a guard resistor such as J shown inmy'copending applicationreferred to'above.

It will be noted that in the line circuit arrangements 'of Figs. 4 and .5, only .tWo andfthree spring .sets respectively are 'required onthefcombined service meterandput-off relay. Inother applications, however, it may be necessary tto use four :spring sets, .as zshownin the constructional embodiment :illustrated in Figs. .-1 :to 3 or-an even greater rnumber.

:Although certain'embodiments ofthe. invention have fbeen shown Yand described "for -thelpurpose of illustration, it will be understood that modiiications and adaptations thereof occurring to those skilled in the art may be made Without departing from the scope of the invention as dened in the appended claims.

What I claim is:

i. In an automatic or semi-automatic telecommunication exchange system, a sbscribers line, electrical contacts over which said line is normally connected to component apparatus at the exchange, an electromagnet individual to said subscribers line, call metering mechanism, means responsive to a predetermined energization of said magnet for opening said contacts and means responsive to a greater predetermined energization of said magnet for actuating said call metering mechanism.

2. A system according to claim l wherein said magnet individual to said subscribers line comprises a magnet core and a Winding on said core, and wherein said second-mentioned means comprises a first armature pivotally mounted adjacent one end of said core for actuating said counting mechanism and said first-mentioned means comprises a second armature pivotally mounted adjacent the other end of said core for actuating said electrical contacts.

3. In an automatic or semi-automatic telecommunication system, a subscribers line, electrical contacts individual to said subscribers line, a line relay having a winding normally connected to a subscribers line conductor over said electrical contacts, an electromagnet and a counting mechanism individual to said subscribers line, means responsive to a predetermined energization of said magnet for opening said contacts and means responsive to a predetermined greater energization of said magnet for actuating said counting mechanism.

4. A system according to claim 3 wherein said magnet is provided with a single winding connected at one end to a conductor individual to said subscribers line and at the other end to a common return point.

5. In an automatic or semi-automatic telecommunication system, a subscribers line comprising a rst and a second line conductor, a subscribers station connected to said line and including means for closing a loop connection between said line conductors to initiate a call, a line nder start circuit, at least two pairs of normally closed electrical contacts and first and second ohmic resistances individual to said subscribers line, the first resistance having one end connected over a pair of said normally closed contacts to said first line conductor and the other end permanently connected to a common return point and the said second resistance having one end connected over another pair of normally closed contacts to said second line conductor and the other end connected to said line iinder start circuit, an electromagnet and a counting mechanism individual to said subscribers line, means responsive to a predetermined energization of said magnet for opening said contacts, and means responsive to a greater predetermined energization of said magnet for actuating said counting mechanism.

6. A system according to claim 5 further comprising a connection from said other end of said second ohmic resistance over further normally closed contacts to a test conductor individual to said subscribers line and means responsive to said predetermined energization of said magnet for opening said further contacts.

7. A combined service meter and relay comprising a core, a winding on said core, a pair of side return pole pieces extending beyond the ends of said core, a counting mechanism, a set of contact springs, a first armature pivotally mounted between said pole pieces adjacent one end of said core for actuating said counting mechanism responsive to a predetermined energization of said winding and a second armature pivotally mounted between said pole pieces adjacent the other end of said core for actuating said contact springs responsive to a predetermined lesser energization of said winding.

8. A combined service meter and relay comprising a mounting plate, a spring set mounted on a support, means for securing said support to said mounting plate, a magnet assembly including a magnet, counting mechanism, a first armature adjacent one end of said magnet for actuating said counting mechanism, a second armature adjacent the other end of said magnet, and means for detachably securing said magnet assembly to said spring set support, said spring set and said second armature being so arranged that they enter into cooperative relation when said magnet assembly is mounted in position on said spring set support.

9. A combined service meter and relay according to claim 8 in which said magnet assembly further comprises a pair of side return pole pieces provided with projecting flanges adapted to slide in grooves provided in said spring set support.

GERALD DEAKIN. 

